Method and device for detecting super capacitor in pitch system

Abstract

The embodiment of the invention provides a method and a device for detecting a super capacitor in a pitch system. The method comprises the following steps of: acquiring a charging start time in the pitch system in which a charger uses a PID algorithm to control the charging of the super capacitor, and an output current in a subsequent process, wherein the control input quantity adopted by the PIDalgorithm is the voltage deviation between a given voltage value and an actual voltage value of the super capacitor, the given voltage value is a fixed value, and the voltage deviation at the chargingstart time is 0; calculating the voltage deviation according to the output current and the control logic of the PID algorithm, and taking the change amount of the voltage deviation as the change amount of the actual voltage of the super capacitor in the charging process; and calculating the capacitance value of the super capacitor according to the change amount of the actual voltage of the supercapacitor in the charging process and the output current in the corresponding time period. According to the scheme provided by the invention, the capacitance value of the super capacitor in the pitchsystem of the wind turbine can be detected quickly, conveniently and accurately, the detection process does not need to be stopped, and the online detection can be realized.

Description

technical field [0001] The invention relates to the technical field of wind power, in particular to a method and device for detecting a supercapacitor in a pitch control system. Background technique [0002] When the wind turbine (referred to as "wind turbine") is in normal operation, when the wind speed exceeds the rated wind speed of the unit, in order to control the power output, the pitch control system keeps the speed of the wind rotor constant by controlling the pitch angle of the blades. When the wind turbine fails, the pitch control system will perform an emergency propeller retraction function to realize pneumatic braking and ensure the safety of the unit. In the case of normal power supply from the grid, the pitch control system relies on the grid to work; when the grid fails (such as grid power failure or low voltage ride through), the pitch control system needs to have a backup power supply to power the pitch operation, in order to prevent In the event of a majo...

AI Technical Summary

Problems solved by technology

[0006] 1) In the shutdown mode of the wind turbine, cut off the output of the charger, consume the energy of the supercapacitor through energy-consuming equipment such as a motor, and then turn on the charger to charge the supercapacitor, and test the capacitance of the supercapacitor during the charging process; Because the output of the charger needs to be cut off first, the method must be tested in the shutdown mode, and online detection cannot be realized (detection when the wind turbine is running); in addition, this method is not conducive to the realization of automatic testing, because automatic testing can only use timing measurement When the automatic measurement time is up, all wind turbines will be disconnected from the grid for capacity detection, which will affect the power generation on the one hand, and on the other hand, may cause fluctuations in the grid due to the batch disconnection of wind turbines; while the manual test mode Next, because the charger needs to be cut off, for the sake of safety, the three blades are generally tested one by one, so the whole test takes a long time, generally takes 15 minutes. For the entire wind farm, the loss of power generation cannot be underestimated;

[0007] 2) During the operation of the wind turbine, directly cut off the output of the charger for a period of time, wait for the supercapacitor to drop to a certain value, and then turn on the charger to charge the supercapacitor; the disadvantage of this method is: since the purpose of detecting the supercapacitor is In order to monitor the performance of the supercapacitor, cutting off the charger without knowing the performance of the supercapacitor has certain hidden dangers to the safety of the wind turbine;

[0008] 3) Use a discharge device to manually detect the discharge of the supercapacitor. This method requires shutdown and testers to board the wind turbine for testing, and its labor and time costs are high.

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